#print .so 's related glibc version'
objdump -T your_library.so | grep -E 'GLIBC_[0-9]+\.[0-9]+' | sort -V | tail -n 1

readelf -sV your_library.so | grep -B1 'GLIBC_' | grep -o 'GLIBC_[0-9.]\+'

ldd --version
